1. Technical Field
Exemplary embodiments relate to a thermoelement and a wearable device including the thermoelement, and more particularly, to a thermoelement in which a plurality of thermoelectric materials are connected in a structure similar to a watch chain, thereby flexibly correspond to a variety of shapes, and a wearable device including the thermoelement.
2. Related Art
A thermoelement refers to an element using the effect that comes from interaction between heat and electricity. In general, the thermoelement includes a heat source, a heat sink and a thermopile. The thermopile includes a plurality of thermocouples (thermoelectric elements) connected in series, and is used to convert a portion of thermal energy to electrical energy.
In terms of a type, the thermoelement may be a thermistor, an element using the Seebeck effect, a Peltier element, and the like. Here, the thermistor refers to an element using a change in temperature of electrical resistance and the element using the Seebeck effect refers to an element using the Seebeck effect that is a phenomenon in which a current is produced due to a temperature difference. The Peltier element refers to an element using the Peltier effect that is a phenomenon in which the absorption or the production of heat occurs due to a current.
In general, the thermoelement is formed using a semiconductor material. To form thermocouples, semiconductor materials are electrically connected in series and thermally connected in parallel and form two junctions. Typically, semiconductor materials include an N-type semiconductor material and a P-type semiconductor material. In a typical thermoelement, electrically conductive connection is formed between a P-type semiconductor material and an N-type semiconductor material. Further, carriers migrate from a hot junction to a cold junction as a result of thermal diffusion and induce a current.
A relatively high Seebeck constant and a sufficient temperature difference are required to produce electricity from thermal energy using the thermoelement. In the thermoelement according to the related art, for example, Korean Patent Registration No. 10-1384981, registered on Apr. 8, 2014, a method of increasing a thickness of a thermoelectric material is employed to realize a sufficient temperature difference. However, in the method of increasing the thickness of the thermoelectric material, it is difficult to realize a desired temperature or more due to electrical resistance and heat of the thermoelectric material. Further, a large amount of materials may be used.
In this regard, the thermoelement may be flexibly configured. In this case, the thermoelement may be significantly thin in a thickness direction compared to a lengthwise direction and thus, a sufficient temperature difference between a heat sink and a heat source may not be maintained and the thermoelement may not efficiently function.